1. Field of the Invention
The present invention relates in general to a method and apparatus for controlling the flow of fluids from a subsurface well, i.e., a well positioned below the surface of the water. More particularly, the present invention provides a method and apparatus for controlling and plugging an undersea oil and/or gas well.
2. Description of the Related Art
In the production of fluids such as petroleum and/or natural gas from subterranean formations, accidents can occur due to human and equipment malfunctions or the like, thereby occasionally producing a condition known as blowout. In such instances, the flow of fluids from a subterranean formation under substantial pressure is unrestricted, with the fluids flowing to the surface, i.e., a sea floor or a land surface. In such instances, it is desirable that a method and apparatus be available for controlling or stopping the flow of such petroleum and/or natural gas because a valuable resource is being wasted and because such fluids pollute the environment when released in an uncontrolled manner.
A number of techniques have been tested and used for controlling the flow of fluids from subterranean formations. For example, U.S. Patent Publication No. US 2002/0162657 A1 discloses a method and apparatus for plugging a well bore using a device to perforate the well casing, and then pumping in cement and squeezing the cement through the perforations and into the formation therearound. U.S. Patent Publication No. US 2009/10277637 A1 discloses a method of plugging and abandonment of an undersea oil well. This method involves severing a well string that extends into an oil well from an oil platform. U.S. Pat. No. 4,417,624 discloses a method and apparatus for controlling the flow of fluids from an offshore oil well involving passing a continuous pipe from a well platform into the open well bore and then pumping a plugging material such as cement into the well bore through the continuous pipe.
In another commonly used method, additional well bores are drilled to intersect with the uncontrolled well bore, so that a plugging fluid such as cement, drilling mud or the like can be pumped into the formation to kill the well. Furthermore, other conventional techniques have involved the use of explosives and the like.
In many instances, blowouts occur during drilling operations. In such instances, it is quite common for the drill ship or drilling rig to move away from the well quickly when the blowout occurs; and in some instances, the drilling rig explodes and is blown away from the well head. As a result, as in the situation with the BP Deepwater Horizon accident, the well bore may be left open at the well head on the ocean floor as a result of equipment malfunction and the like, or at the well head on land. In such instances, the well bore is substantially open so that the flow of petroleum and/or natural gas is unimpeded, thereby resulting in an environmental and economic catastrophe.
Accordingly, it is an object of the present invention to provide a method and apparatus for controlling and/or stopping the control of fluids from such open well bores.